Overdrive has a lot of new resources to help library users/patrons with borrowing eBooks and audiobooks.
One that was pointed out recently by Ann at Essex Free are the How-To videos.
Check them out here: http://www.overdrive.com/help-videos/ They offer help with the general website and with each supported device like Kindles and iPhones. You can even embed them on your website if you have a digital resources page.